Withania somnifera a popular Indian medicinal plant also known as Ashwagandha, Indian ginseng, and winter cherry belongs to the Solanaceae or nightshade family. It has been an important herb in the ayurvedic and indigenous medical system for over 3000 years.
It is an erect, greyish, subshrub with inconspicuous yellow or greenish flowers followed by small, spherical, orangish-red berries containing yellow, kidney-shaped seeds. It grows three-to-five feet tall, mainly on waste land, but is cultivated widely as the whole plant; most commonly the root and leaf are used medicinally. The fruits from several of its species are edible, and some are used in traditional medicine.
The species name somnifera means “sleep-inducing” in Latin. The common name comes from the Sanskrit ashwagandha, i.e., ashwa for horse, and gandha for smell, hence the common idea that the name means “smells like a horse.” The species is widely distributed in the northwestern Indian states of Gujarat, Madhya Pradesh, Maharashtra, Rajasthan, Uttar Pradesh, and the Punjab plains extending to the mountainous regions of Himachal Pradesh and Jammu. It also is cultivated in parts of Madhya Pradesh and Rajasthan. Northwest of India, its habitat extends into the Pakistani provinces of Sindh and Baluchistan, and on into Afghanistan. To the southeast of India, it occurs in Sri Lanka. In China, it is reported to grow in the western provinces of Gansu and Yunnan.
Ashwagandha is one of the rasayana herbs in Ayurveda—one of the herbs that purportedly promotes youth and longevity and alleviates suffering. It is thought to be especially rejuvenative for men; to strengthen bone marrow, muscle, and semen; and to imbue the user with intellectual facility, in addition to long life and youthful vitality. However, it also is believed to be quite helpful to the elderly by providing energy and relieving pain, inflammation, and nervous debility.
The roots of this plant have been used as an adaptogen and to treat arthritis, asthma, dyspepsia, hypertension, rheumatism, and syphilis. Earlier pharmacological investigations of Withania somnifera have revealed its antiinflammatory, antioxidant, immunomodulatory, and tumor cell proliferation inhibitory activities.
The leaves are used to expel worms and are combined with warm castor oil (Ricinis communis, Euphorbiaceae) on carbuncles, inflammations, and swellings. The Masai use the leaf juice for conjunctivitis. The fresh bruised berries are used on ringworm. The fruits or seeds are used to coagulate milk. The seeds also are used as a masticatory. A bark infusion is used in Lesotho internally for asthma and externally for bedsores. The tender shoots are eaten as a vegetable in India.
The dried root and the whole plant are used in the traditional medicine systems of Ayurveda, Siddha, Sowa-Rigpa (Amchi), and Unani, as well as in Indian folk medicine. The materials of commerce are obtained from both cultivated and wild-collected sources, mainly in India.
In countries where the Ayurvedic system of medicine is officially recognized and practiced (e.g., India, Bangladesh, Bhutan, Malaysia, Nepal, and Sri Lanka), the powdered dried root of Ashwagandha is used, as a component of preparations, for treating inflammatory disorders, phthisis (any wasting or atrophic disease, weakness, diseases due to vata dosha), and male impotence.
In countries where the Unani system of medicine is officially recognized and practiced (e.g., Bangladesh, India, Malaysia, Pakistan, and Sri Lanka), the dried mature root, referred to as “asgand,” is used as a component of medicinal formulations to treat leucorrhoea, spermatorrhoea, decreased viscosity of semen, sexual debility, lumbago, and arthritis.
In Siddha medicine—a Dravidian system of medicine originating in the southeastern Indian state of Tamil Nadu, now also practiced in the neighboring states of Karnataka, Kerala, and Andhra Pradesh, as well as in parts of Malaysia, Singapore, and Sri Lanka—the dried root (purified before use), referred to as amukkara, is used as a component of formulations indicated for treatment of conditions including oligospermia, lancinating pain, loss of body strength, anemia, convulsions/seizures/fits, disordered humor, eczema, edema/swelling, and tuberculosis.
Dhuley et al found that the root extract of Ashwagandha prevented the rise of experimentally induced LPO in rabbits & mice. Withaferin A and Sitoindoside VIII-X exhibits fairly potent anti-arthritic, anti-inflammatory, antioxidant & immuno modulant activities, they also increase in the levels of SOD, CAT, GPX in brain & the steroidal lactone W. A (Bhattacharya et al, 1997). The administration of Ashwagandha Rasayana significantly reduced the lung tumor nodule formation and also reduced leucopenia induced by cyclophosphamide treated experimental animals, indicating its usefulness in cancer therapy (Menon L, 1997 and Davis L, 1998). Withania increase the WBC count, reduce leucopenia. They also increased bone marrow cellularity & normalised the ratio of hormachromatic erythrocytes & polychromatic erythrocytes (Davis L, 1998). A methanolic & 80% ethanolic extract of Withania somnifera displayed significant anti-inflammatory activity on carrageenan-induced paw edema (Hindawi-al MKIH et al, 1989).
The main constituents of Ashwagandha are alkaloids and steroidal lactones. Among the various alkaloids, withanine is the main constituent. The other alkaloids are somniferine, somnine, somniferinine, withananine, pseudowithanine, tropine, pseudotropine, 3agloyloxytropane, choline, cuscohygrine, isopelletierine, anaferine and anahydrine. Two acyl steryl glucoside viz. sitoindoside VII and sitoindoside VIII have been isolated from root. The leaves contain steroidal lactones, which are commonly called withanolides. The withanolides have C28 steroidal nucleus with C9 side chain, having six membered lactone rings. Withaferin A a steroidal lactone is the most important withanolide isolated from the extract of the leaves and dried roots of Withania somnifera. 
Qamar et al in 2012 reported the active phytochemical and pharmacological components of Withania somnifera. The roots are reported to contain alkaloids, amino acids, steroids, volatile oil, starch, reducing sugars, glycosides, hentriacontane, dulcitol, withaniol, an acid and a neutral compound. Many biochemically heterogeneous alkaloids have been reported in the roots. Basic alkaloids include cuscohygrine, anahygrine, tropine, pseudotropine, anaferine, isopelletierine, withananine, withananinine, pseudo-withanine, somnine, somniferine, somniferinine. Neutral alkaloids include 3-tropyltigloate and an unidentified alkaloid. Other alkaloids include withanine, withasomnine, and visamine. The leaves of the plant (Indian chemotype) are reported to contain 12 withanolides, 5 unidentified alkaloids, many free amino acids, chlorogenic acid, glycosides, glucose, condensed tannins, and flavonoids (Khare, 2007). The stem of the plant contains condensed tannins and flavonoids. The bark contains a number of free amino acids (Anonymous, 1982).
Patel et al. (2009) extracted powdered root of W. somnifera with ethylacetate and developed fingerprint profile and analysis of withaferin A in young and old root samples. Chatterjee et al. (2010) studied the metabolic fingerprinting of W. somnifera leaf and root extracts by using serial exhaustive extraction using hexane, 90% methanol, 70% methanol, chloroform and butanol. Rao et al. (2012) used methanol to extract withanolides from the roots of the W. somnifera and the extract was subjected to HPLC for detection. Singh et al. (2011) performed TLC to identify the different constituents present in different extracts of ashwagandha roots. Different solvent systems such as acetonitrile:water (75:25) and toluene:ethyl acetate:acetic acid (65:33:2). HPTLC method has been developed by Sharma et al. (2007) for the estimation of withaferin-A and withanolide-A in different plant parts such as leaf, root, stem and fruit of two morphotypes of W. somnifera. 
Ghosal et al, US patent publication 2004/0166184, reveals composition of withania somnifera from roots and leaves containing 8-25% withanolide glycosides and sitoindosides, about 25-75% Oligosaccharides and less than 2% of free withanferin A(aglycone). Ghosal et al U.S. Pat. No. 6,153,198 discloses a high purity Withania Somnifera extract composition from root of Ashwagandha containing at least 3% withanolide glycoside and sitoindoside, at least 3% oligosaccharides and less than 0.5% of cytotoxic withferin A (aglycones) in the form of a high purity stable powder for producing an enhanced cognition effect for the use and to augment the learning facility. U.S. Pat. No. 7,108,870, Sangwan et al, reported an improved process of analytical and quantitative isolation of withaferin A from Withania Somnifera. Patent publication US 20140087009, McNeary et al, discloses a composition including combinations of β-glucan and Withania Somnifera for increasing the immune activity of certain target cytokines ad phagocytosis and reducing cortisol or corticosterone. Sumithradevi et al reported a simple method to purify withanolide A from the roots of Withania somnifera. Uddin et al reported the phytochemical and pharmacological profile of Withania somnifera. WO2012160569, Jayesh Panalal et al discloses a process for extraction of Withanoside IV and V from Ashwagandha roots and its composition.